Allowed values for list_number and list_boolean not converted to arrays

I spent nearly an entire day trying to get the node types and CCK fields migrated from a D5 site to D7. I ran into all sorts of problems, including:

#1078804: 'longtext' columns converted to varchar(255) on migration
#1066268: PHP Notice: undefined index when migrating decimal number

However, the most serious was that my number fields (at least the select lists and checkboxes) weren't migrating at all. After tons of debugging and experimentation, I tracked it down to the fact that nothing is handling the allowed_values conversion for number fields. Works for list_text, but not list_number nor list_boolean. I've got a patch, stay tuned...